Cellular radio telephone set

ABSTRACT

This invention relates to a cellular radio telephone set having a USB peripheral circuit which realizes a USB connection function. When the cellular radio telephone set is connected to an information processing terminal apparatus via a USB cable, a voltage Vbus supplied from the information processing terminal apparatus is regulated and supplied to the USB peripheral circuit. When the cellular radio telephone set is not connected to the information processing terminal apparatus via the USB cable, an application CPU which controls the USB peripheral circuit is shifted to a sleep mode.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a cellular radio telephone setand, more particularly, to a cellular radio telephone set having a USB(Universal Serial Bus) peripheral circuit which realizes a USBconnection function.

[0003] 2. Description of the Prior Art

[0004] Cellular radio telephone sets are desired to have reduced sizeand weight for portability, and their internal batteries are alsoreduced in size and weight. However, a small-size, light-weight internalbattery means a short service life. The cellular radio telephone mustalways be ON to ensure a long standby time because the user does notknow when he/she may receive an incoming call. Therefore, the cellularradio telephone set must reduce its power consumption to prolong thestandby time.

[0005] Recent cellular radio telephone sets are connected to informationprocessing terminal apparatuses such as a personal computer (to besimply referred to as a PC hereinafter) and a PDA (Personal DigitalAssistants), realizing information exchange with the informationprocessing terminal apparatuses and mobile communication using thetelephone network of the cellular radio telephone set. At this time, theinformation processing terminal apparatus and cellular radio telephoneset are connected using, e.g., a USB.

[0006] In the use of the USB, the cellular radio telephone set must benewly equipped with a USB peripheral circuit such as a USB devicecontroller circuit. Power for operating the USB peripheral circuit isfurther required.

[0007] For the USB, a suspend mode is generally prepared. Using thesuspend mode can reduce the power consumption of the USB peripheralcircuit when the cellular radio telephone set is not connected to theinformation processing terminal apparatus.

[0008] Even the suspend mode cannot completely eliminate the powerconsumption of the USB peripheral circuit, and a current of about 500 mAmay flow at maximum. Demands have arisen for a further improvement inthis respect.

SUMMARY OF THE INVENTION

[0009] The present invention has been made in consideration of the abovesituation, and has as its object to provide a cellular radio telephoneset having a USB connection function capable of minimizing the powerconsumption of the internal battery of the cellular radio telephone setboth when the cellular radio telephone set is connected to aninformation processing terminal apparatus via a USB cable and when it isnot connected to it.

[0010] To achieve the above object, according to the first principalaspect of the present invention, there is provided a cellular radiotelephone set having a USB peripheral circuit which realizes a USBconnection function, wherein when the cellular radio telephone set isconnected to an information processing terminal apparatus via a USBcable, a voltage Vbus supplied from the information processing terminalapparatus is regulated and supplied to the USB peripheral circuit, andwhen the cellular radio telephone set is not connected to theinformation processing terminal apparatus via the USB cable, anapplication CPU which controls the USB peripheral circuit is shifted toa sleep mode.

[0011] In the cellular radio telephone set according to the firstprincipal aspect, the sleep mode includes a low-power consumptionoperation mode.

[0012] In the cellular radio telephone set according to the firstprincipal aspect, whether the cellular radio telephone set is connectedto the information processing terminal apparatus via the USB cable isdetermined by detecting presence/absence of the voltage Vbus suppliedfrom the information processing terminal apparatus.

[0013] To achieve the above object, according to the second principalaspect of the present invention, there is provided a cellular radiotelephone set having a USB connection function, comprising a USBconnector which is connected to a USB cable connected to an informationprocessing terminal apparatus including a personal computer, a USBdevice controller circuit for communicating with the informationprocessing terminal apparatus via the USB connector connected to the USBcable, an application CPU which controls the whole USB, a control CPUwhich controls the whole cellular radio telephone set, a regulatorcircuit which converts a voltage Vbus supplied from the informationprocessing terminal apparatus via the USB cable into a voltage for theUSB device controller circuit, and a Vbus detection circuit whichdetects presence/absence of the voltage Vbus.

[0014] In the cellular radio telephone set according to the secondprincipal aspect, the USB device controller circuit comprises a D+pull-up circuit which pulls up a signal D+ for data communication withthe information processing terminal apparatus, a controller whichcontrols the D+ pull-up circuit, and a transmission/reception circuitwhich performs transmission/reception of USB data communication.

[0015] As is apparent from the above aspects, according to the presentinvention, the cellular radio telephone set having the USB connectionfunction can minimize the power consumption of the internal battery ofthe cellular radio telephone set both when the cellular radio telephoneset is connected to an information processing terminal apparatus via aUSB cable and when it is not connected to it.

[0016] The present invention can reduce the power consumption of theinternal battery in the standby state of the cellular radio telephoneset and prolong the standby time.

[0017] The above and many other objects, features and advantages of thepresent invention will become manifest to those skilled in the art uponmaking reference to the following detailed description and accompanyingdrawings which a preferred embodiment incorporating the principle of thepresent invention are shown by way of an illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a block diagram showing the power control arrangement ofthe USB peripheral circuit of a cellular radio telephone set accordingto an embodiment of the present invention; and

[0019]FIG. 2 is a flow chart showing the operation of the cellular radiotelephone set shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] A preferred embodiment of the present invention will be describedin detail below with reference to the accompanying drawings.

[0021] In the present invention, a USB peripheral circuit in a cellularradio telephone set is operated by only power supplied from aninformation processing terminal apparatus such as a PC serving as ahost, preventing the consumption of the internal battery of the cellularradio telephone set. When the cellular radio telephone set is notconnected to the information processing terminal apparatus such as a PC,the application CPU is also shifted to a sleep mode, i.e., low-powerconsumption operation mode, reducing the power consumption of theinternal battery of the cellular radio telephone set.

[0022] The present invention comprises a circuit which regulates avoltage Vbus supplied from the information processing terminal apparatusand supplies the regulated voltage to the USB peripheral circuit, and acircuit which detects Vbus. Vbus is supplied to a USB device controllercircuit to prevent the consumption of the internal battery of thecellular radio telephone set. The application CPU is shifted to thelow-power consumption operation mode to reduce the power consumption ofthe internal battery of the cellular radio telephone set.

[0023]FIG. 1 is a block diagram showing the power control arrangement ofthe USB peripheral circuit of the cellular radio telephone set accordingto the embodiment of the present invention.

[0024] The cellular radio telephone set of the embodiment comprises aUSB connector 1 which is connected to a USB cable connected to aninformation processing terminal apparatus such as a PC, a USB devicecontroller circuit 2 for communicating with the information processingterminal apparatus via the USB connector 1 connected to the USB cable,an application CPU 4 which controls the whole USB, a control CPU 5 whichcontrols the entire cellular radio telephone set, a regulator circuit 6which converts the voltage Vbus supplied from the information processingterminal apparatus via the USB cable into a voltage for the USB devicecontroller circuit 2, and a Vbus detection circuit 7 which detects thepresence/absence of the voltage Vbus.

[0025] The USB device controller circuit 2 comprises a D+ pull-upcircuit 3 which pulls up a signal D+ for data communication with theinformation processing terminal apparatus, a controller 8 which controlsthe D+ pull-up circuit 3, and a transmission/reception circuit 9 whichperforms transmission/reception of USB data communication.

[0026] As shown in FIG. 1, the cellular radio telephone set of theembodiment comprises the regulator circuit 6 which converts 5V Vbus into3.3V and supplies 3.3V to the USB device controller circuit 2. This canprevent the power consumption of the cellular radio telephone set.

[0027] The cellular radio telephone set of the embodiment furthercomprises the Vbus detection circuit 7. When the Vbus detection circuit7 detects the presence of Vbus, the control CPU 5 shifts the applicationCPU 4 to the sleep mode, thereby reducing the power consumption. Whenthe Vbus detection circuit 7 detects the presence of Vbus, the controlCPU 5 wakes up the application CPU 4. The USB device controller circuit2 is so controlled as to pull up D+. A sequence of communicating withthe information processing terminal apparatus such as a PC is realized.

[0028] The cellular radio telephone set of this embodiment will beexplained in more detail with reference to FIG. 1.

[0029] The regulator circuit 6 converts 5V Vbus supplied via the USBconnector 1 into 3.3V, and supplies this regulated voltage (3.3V) to theUSB device controller circuit 2.

[0030] The USB device controller circuit 2 incorporates the pull-upcircuit 3 which pulls up D+ under the control of the controller 8. Thecellular radio telephone set comprises the Vbus detection circuit 7. AVbus detection signal from the Vbus detection circuit 7 is sent to thecontrol CPU 5. The control CPU 5 shifts the application CPU 4 to thesleep mode or wakes it up on the basis of the Vbus detection signal.

[0031] When the cellular radio telephone set is not connected to theinformation processing terminal apparatus such as a PC, no Vbus, D+, orD− is supplied to the cellular radio telephone set. In this state, nopower is supplied to the USB device controller circuit 2. At this time,the Vbus detection circuit 7 detects that no Vbus is supplied. Thecontrol CPU 5 shifts the application CPU 4 to the low-power consumptionoperation mode (e-g-, decreases the operation clock or turns off thepower supply of a specific block). Accordingly, the power consumption ofthe internal battery in the standby state of the cellular radiotelephone set can be reduced.

[0032] When the cellular radio telephone set is connected to theinformation processing terminal apparatus, Vbus is converted into 3.3 Vby the regulator circuit 6 and then supplied to the USB devicecontroller circuit 2. The Vbus detection circuit 7 detects Vbus, and aVbus detection signal is recognized by the control CPU 5.

[0033] The subsequent operation will be explained with reference to theflow chart of FIG. 2.

[0034] If the information processing terminal apparatus and cellularradio telephone set are connected by a USB cable (A-1), the Vbusdetection circuit 7 detects Vbus (connection to the host). At the sametime, power is supplied to the USB device controller circuit 2 (A-2).

[0035] The control CPU 5 wakes up the application CPU 4 on the basis ofa Vbus detection signal from the Vbus detection circuit 7 ((A-3) and(A-4)). After the end of activation, the application CPU 4 initializesthe USB device controller circuit 2 (A-5).

[0036] The controller 8 and D+ pull-up circuit 3 of the USB devicecontroller circuit 2 pull up D+(A-6). In response to D+ pull-upoperation, USB communication starts (A-7).

[0037] Note that execution of D+ pull-up operation before activation ofthe application CPU causes a problem in USB connection and should beavoided.

What is claimed is:
 1. A cellular radio telephone set having a USBperipheral circuit which realizes a USB connection function, whereinwhen the cellular radio telephone set is connected to an informationprocessing terminal apparatus via a USB cable, a voltage Vbus suppliedfrom the information processing terminal apparatus is regulated andsupplied to the USB peripheral circuit.
 2. A cellular radio telephoneset having a USB peripheral circuit which realizes a USB connectionfunction, wherein when the cellular radio telephone set is not connectedto an information processing terminal apparatus via a USB cable, anapplication CPU which controls the USB peripheral circuit is shifted toa sleep mode.
 3. A cellular radio telephone set having a USB peripheralcircuit which realizes a USB connection function, wherein when thecellular radio telephone set is connected to an information processingterminal apparatus via a USB cable, a voltage Vbus supplied from theinformation processing terminal apparatus is regulated and supplied tothe USB peripheral circuit, and when the cellular radio telephone set isnot connected to the information processing terminal apparatus via theUSB cable, an application CPU which controls the USB peripheral circuitis shifted to a sleep mode.
 4. A cellular radio telephone set having aUSB peripheral circuit which realizes a USB connection function, whereinwhen the cellular radio telephone set is not connected to an informationprocessing terminal apparatus via a USB cable, an application CPU whichcontrols the USB peripheral circuit is shifted to a sleep mode, and whenthe cellular radio telephone set is connected to the informationprocessing terminal apparatus via the USB cable, the application CPU iswaked up.
 5. A telephone set according to claim 2, wherein the sleepmode includes a low-power consumption operation mode.
 6. A telephone setaccording to claim 3, wherein the sleep mode includes a low-powerconsumption operation mode.
 7. A telephone set according to claim 4,wherein the sleep mode includes a low-power consumption operation mode.8. A telephone set according to claim 1, wherein whether the cellularradio telephone set is connected to the information processing terminalapparatus via the USB cable is determined by detecting presence/absenceof the voltage Vbus supplied from the information processing terminalapparatus.
 9. A telephone set according to claim 2, wherein whether thecellular radio telephone set is connected to the information processingterminal apparatus via the USB cable is determined by detectingpresence/absence of the voltage Vbus supplied from the informationprocessing terminal apparatus.
 10. A telephone set according to claim 3,wherein whether the cellular radio telephone set is connected to theinformation processing terminal apparatus via the USB cable isdetermined by detecting presence/absence of the voltage Vbus suppliedfrom the information processing terminal apparatus.
 11. A telephone setaccording to claim 4, wherein whether the cellular radio telephone setis connected to the information processing terminal apparatus via theUSB cable is determined by detecting presence/absence of the voltageVbus supplied from the information processing terminal apparatus.
 12. Atelephone set according to claim 5, wherein whether the cellular radiotelephone set is connected to the information processing terminalapparatus via the USB cable is determined by detecting presence/absenceof the voltage Vbus supplied from the information processing terminalapparatus.
 13. A cellular radio telephone set having a USB connectionfunction, comprising a USB connector which is connected to a USB cableconnected to an information processing terminal apparatus including apersonal computer, a USB device controller circuit for communicatingwith the information processing terminal apparatus via the USB connectorconnected to the USB cable, an application CPU-which controls the wholeUSB, a control CPU which controls the whole cellular radio telephoneset, a regulator circuit which converts a voltage Vbus supplied from theinformation processing terminal apparatus via the USB cable into avoltage for the USB device controller circuit, and a Vbus detectioncircuit which detects presence/absence of the voltage Vbus.
 14. Atelephone set according to claim 13, wherein said USB device controllercircuit comprises a D+ pull-up circuit which pulls up a signal D+ fordata communication with the information processing terminal apparatus, acontroller which controls said D+ pull-up circuit, and atransmission/reception circuit which performs transmission/reception ofUSB data communication.